Furnaces are used in a wide range of metallurgical processes. Many furnaces include a first opening through which feed materials can be fed to the furnace and a second opening through which an exhaust gas or flue gas can be removed from the furnace, as well as other openings for final products and by-products to be recovered. Typical materials that are fed to furnaces in metallurgical processes include concentrates or ores, fluxes, fuel such as coal or coke, and air or oxygen. The feed materials undergo reaction with the contents of the furnace to produce desirable metallurgical products. Exhaust gases are produced during the process and the exhaust gases are removed through the exhaust outlet of the furnace. Dust generated from the feed material descending in the furnace can also find its way passing with the exhaust gases and removed through the exhaust outlet.
One type of furnace that is finding increased use in metallurgical processing is the top entry submerged lance furnace. Top entry submerged lance furnaces comprised a furnace body or vessel. A feed opening is provided in the top of the furnace. An exhaust opening is provided laterally of the feed opening. Furnace feed material is passed to the furnace through the feed opening. A lance is inserted through a separate opening into the furnace. A gas and, optionally, a fuel, are passed through the lance into the furnace. The tip of the lance extends into the molten contents of the furnace. Injection of gas through the lance agitates the molten contents of the furnace and promotes the metallurgical reactions. The exhaust gases produced by the metallurgical process exit the furnace through the exhaust opening. One type of top entry submerged lance furnace is sole by the present applicant under the ISASMELT™ trade mark.
Operating personnel are frequently required to be physically present close to the feed opening of the furnace. Therefore, it is desirable that gases or dust from the furnace do not exit the furnace through the feed opening. However, in practice, it can be difficult to prevent furnace gases or dust exiting through the feed opening.
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